A Democrat-sponsored bill redefining Colorado elections to include same-day voter registration and sending ballots by mail to all voters passed the Senate without support from Republicans who raised concerns about fraud.

Colorado Democrats advanced an elections overhaul Thursday that includes mailing ballots to every registered voter and allowing same-day registration — proposed changes that have Republicans nervous about the potential benefit to Democrats.

Colorado Democrats are planning sweeping changes to how elections are run in the state. Democrats want to allow same-day voter registration and to require that every registered voter gets a ballot by mail.